<!DOCTYPE html>
<html>
  <head>
    <title>
      audiochannelmerger-input.html
    </title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <script src="/webaudio/resources/audit-util.js"></script>
    <script src="/webaudio/resources/audit.js"></script>
    <script src="/webaudio/resources/merger-testing.js"></script>
  </head>
  <body>
    <script id="layout-test-code">
      let audit = Audit.createTaskRunner();

      // Task: Check if an inactive input renders a silent mono channel in the
      // output.
      audit.define('silent-channel', (task, should) => {
        testMergerInput(should, {
          numberOfChannels: 6,

          // Create a mono source buffer filled with '1'.
          testBufferContent: [1],

          // Connect the output of source into the 4th input of merger.
          mergerInputIndex: 3,

          // All channels should contain 0, except channel 4 which should be 1.
          expected: [0, 0, 0, 1, 0, 0],
        }).then(() => task.done());
      });


      // Task: Check if a stereo input is being down-mixed to mono channel
      // correctly based on the mixing rule.
      audit.define('stereo-down-mixing', (task, should) => {
        testMergerInput(should, {
          numberOfChannels: 6,

          // Create a stereo buffer filled with '1' and '2' for left and right
          // channels respectively.
          testBufferContent: [1, 2],

          // Connect the output of source into the 1st input of merger.
          mergerInputIndex: undefined,

          // The result of summed and down-mixed stereo audio should be 1.5.
          // (= 1 * 0.5 + 2 * 0.5)
          expected: [1.5, 0, 0, 0, 0, 0],
        }).then(() => task.done());
      });


      // Task: Check if 3-channel input gets processed by the 'discrete' mixing
      // rule.
      audit.define('undefined-channel-layout', (task, should) => {
        testMergerInput(should, {
          numberOfChannels: 6,

          // Create a 3-channel buffer filled with '1', '2', and '3'
          // respectively.
          testBufferContent: [1, 2, 3],

          // Connect the output of source into the 1st input of merger.
          mergerInputIndex: undefined,

          // The result of summed stereo audio should be 1 because 3-channel is
          // not a canonical layout, so the input channel 2 and 3 should be
          // dropped by 'discrete' mixing rule.
          expected: [1, 0, 0, 0, 0, 0],
        }).then(() => task.done());
      });


      // Task: Merging two inputs into a single stereo stream.
      audit.define('merging-to-stereo', (task, should) => {

        // For this test, the number of channel should be 2.
        let context = new OfflineAudioContext(2, 128, 44100);
        let merger = context.createChannelMerger();
        let source1 = context.createBufferSource();
        let source2 = context.createBufferSource();

        // Create a DC offset buffer (mono) filled with 1 and assign it to BS
        // nodes.
        let positiveDCOffset = createConstantBuffer(context, 128, 1);
        let negativeDCOffset = createConstantBuffer(context, 128, -1);
        source1.buffer = positiveDCOffset;
        source2.buffer = negativeDCOffset;

        // Connect: BS#1 => merger_input#0, BS#2 => Inverter => merger_input#1
        source1.connect(merger, 0, 0);
        source2.connect(merger, 0, 1);
        merger.connect(context.destination);
        source1.start();
        source2.start();

        context.startRendering().then(function(buffer) {

          // Channel#0 = 1, Channel#1 = -1
          should(buffer.getChannelData(0), 'Channel #0').beConstantValueOf(1);
          should(buffer.getChannelData(1), 'Channel #1').beConstantValueOf(-1);

          task.done();
        });
      });


      audit.run();
    </script>
  </body>
</html>
